A great many bookmarks have been developed over the years; however, one of the problems has been that the bookmark will slide down into the book and be difficult to locate or will fall out entirely. This problem occurs not only when the bookmark is being used in its marking function but is also a problem when the user is reading the book and merely wants to insert the bookmark between the pages for storage purposes while the book is in use. None of the prior art provides a retaining hook element at the upper end of the bookmark which receives the upper end of the bound edge of the book and positively maintains the upper portion of the mark in upwardly extended position above the top edge of the book for ready access. By preventing the bookmark from sliding down between the pages, the bookmark will always be accessible. Also a number of different page referencing concepts have been used in the past; however, none of these concepts provide a highly versatile referencing system such as the present invention.